Spray gun



Nov. 6,- 1962 B. H. MATTHEWS 3,062,453

SPRAY GUN Filed July 14, 1959 2 Sheets-Sheet 1 jfgl Ernie/114 M #arrvzws United tates Patent 3,062,453 Patented Nov. 6, 1962 3,062,453 SPRAY GUN Benjamin H. Matthews, Hudson, Ohio, assignor to Lucerne Products, Inc., Northfield, Ohio, a corporation of Ohio Filed July 14, 1959, Ser. No. 827,073 3 Claims. (Cl. 239143) This invention relates to improvements in a spray gun and more particularly to a spray head thereof.

One of the objects of the present invention is to provide a spray gun wherein the operators finger is adapted to cover or uncover an opening therein for controlling cut off or energization of the spray.

A further object of the present invention is to provide a spray gun with means for controlling the volume of liquid sprayed, and means for agitating the liquid in an associated storage container when Spraying is cut off.

A further object of the present invention is to provide a spray gun characterized by its inexpensive manufacturing cost, ease of assembly of its component parts, structural simplicity, strong and sturdy nature, ease of operation or use, multiplicity of functional advantages for some component parts, and/or low operating cost.

Other features of this invention reside in the arrangement and design of the parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings, 1

FIG. 1 is a side elevational view of the spray gun attached to a source of fluid pressure;

FIG. 2 is a front view of the spray head and spray nozzle of the spray gun taken generally along the line 22 in FIG. 1;

FIG. 3 is a rear end view of the fluid pressure inlet taken generally along the line 3-3 in FIG. 1;

' FIG. 4 is a horizontal sectional view taken generally along the line 44 in FIG. 2 through the spray head;

FIG. 5 is a vertical sectional view taken generally along the line 5-5 in FIG. 2 through the spray head;

' FIG. 6 is partially a side elevational view and partially a longitudinal sectional view similar to FIG. 5 but "with the component parts of the spray head in a different axial adjustment position; while FIG. 7 is a horizontal. sectional view taken generally along the line 7-7 in FIG. 5.

Before the spray gun here illustrated is specifically described, it is to be understood that the invention here involved is not limited to the structural details or arrangement of parts here shown since a spray gun embodying the present invention may take various forms. It also is to be understood that the phraseology or terminology herein employed is for purposes of description and not I of limitation since the scope of the present invention is denoted by the appended claims.

While the present invention might be adapted to various machines it has been chosen to show the same as a spray gun for spraying paint by air pressure. However, it should be readily understood that the illustrated spray gun may spray not only paint, but any liquid, and may use not only air, but also any other suitable fluid pressure.

In FIG. 1, spray gun 10 includes spray head 11 detachably secured to a liquid container or paint pot 12 and a source of fluid or air pressure, such as vacuum cleaner hose 14 attached to the pressure side of a. vacuum cleaner and in tapered bore 161 of spray head 11 for supplying a large volume of low pressure air. Spray, gun 19 is conhead 11 has three component parts with each made of any suitable material, such as linear polyethylene. These parts of spray head 11 include a body portion 16, a sleeve 18, I

and a ring or plug member 20.

An adapter 22 is secured to body portion 16 by four screws 24. Adapter 22 has screw threads 22a adapted to be screwed onto corresponding screw threads 12a on container 12 for securing to spray head 11 this container 12 of paint to be sprayed.

Spray head 11 and body portion 16 have a plurality of flow conduits or passageways. A liquid conduit or passageway 26 in FIG. 5 is provided for conveying the paint from container 12 to spray nozzle 13. This liquid conduit 26 includes the bore 28a of tube 28, having its bottom end extending down to the bottom of the container 12 in FIG. 1 and having the peripheral surface of its upper end in FIG. 5 secured in bore 16a of body portion 16; and bores 16b and 16c in body portion 16 in FIG. 5 leading to spray nozzle 13.

Body portion 16 has a first fluid conduit 30 for conducting the air under pressure from hose 14 down onto the surface of the paint in container 12 so as to force the paint up through liquid conduit 26 to nozzle 13. In this conduit 30, the air under pressure travels through first opening 16d in FIG. 5 connected to the source of air pressure by hose 14, bore 16c, bore or conduit portion 16f, bore 16g, and second opening 16h leading down into the container for conveying the air down against the top surface of the paint in container 12 for forcing this paint through the spray nozzle 13. A third opening 16j is adapted to be covered or uncovered with the operators finger to respectively cause the spraying action by applying the pressure of the air'down on the surface of the paint in container 12 or for cutting off the spraying action by releasing the air pressure there. When opening 16 is covered by the finger, paint spraying occurs because the air under pressure travels from opening 16d through opening 16h. If opening 16 is uncovered, spraying is stopped by permitting the air to exhaust to atmosphere through third opening 16 This construction causes the spraying action to stop immediately when opening 161' is uncovered. It should be noted that bore ,or conduit portion 16 is connected to the third opening 16 with a cross sectional area in FIG. 5 larger than the cross sectional areas of the openings 16d and 16h, and this enlarged bore portion 16 is located in the air travel path between openings 16d and 16h. Hence, the air pressure drop, because of the relative cross sectional sizes of the flow passageways, during air flow is greater from opening 16d to 16h than from opening 16d to 16 .v Therefore, when the operator removes his finger to uncover opening 16 the air pressure onthe paint in container 12 is immediately reduced to immediately stop paint spraying because: (1) incoming pressure air entering opening 16d will immediately vent outwardly through opening 16f, and (2) the static pressure on the paint in container 12 is immediately relieved by having the air pressure immediately vent from opening 1612 to the atmosphere through opening 16 Spray head 11 includes a second fluid conduit 32 in FIG. 4 extending in the left hand direction in FIG. '4 from tapered bore 161 in FIG. 4 at the inlet of the air pressure, and around island 162 to fourth opening 34 in the zone around spray nozzle 13. This conduit 32 includes a flow passagewayfor the air under pressurev from bore 16t through passage 16k; annular recess 16q around.

21) arranged concentrically therewith to form a fluid controlling opening 201 concentric with spray nozzle 13.

Spray head 11 includes ring member 18 mounted on body portion 16 for axial movement relative to spray nozzle 13 for providing several advantageous operating features to be discussed in more detail hereinafter. If sleeve 18 is rotated on body portion 16, projection or dimple 18d, traveling in helical groove 1611 on body portion 16, will cause sleeve 18 and member 20 to move relative to body portion 16 between the positions shown in FIGS. and 6.

The component parts 16, 18 and 20 are easily assembled. Radially outwardly extending annular flange 20b of member 29 is pushed axially through the bore of sleeve 18 until it snaps into annular recess 18b in sleeve 18. The plastic resin material of sleeve 18 permits this distortion. Then, cylindrical bore 18c of sleeve 18 is telescoped over cylindrical periphery 16m of body portion 16 until projection or dimple 13d in bore 18:: snaps into helical groove 1611. External chamfer 16p on body portion 16 permits this assembly operation to take place without requiring an axially extending groove in surface 16m to permit projection 18d to reach groove 1611. Also, if parts 16, 18 and 20 are made of linear polyethylene, they have enough resiliency to permit this assembly action to take place easily.

The mode of operation will now be readily apparent by considering the following three operational features. First, the spray is easily turned on or off for controlling the spraying of the paint in container 12. When the operators finger does not cover hole 16 in FIG. 5, the spray cut off condition exists to cut off the air pressure to the surface of the paint in container 12 by permitting the air entering opening 16a to exhaust to the atmosphere through hole 16 so as to stop the paint spraying. When hole 16 is covered by the operators finger, a spray energized condition exists for applying spraying air pressure from hose 14 in FIG. 1 down onto the surface of the paint in container 12 for causing paint spraying through nozzle 13. When spraying occurs, the paint emerging from nozzle 13 is caused to disperse by the air traveling through annular opening 34 and the air traveling from recess 16q in FIG. 5 through passageways 20c, and diametrically opposite nozzle ports 213d located downstream from nozzle 13. The small opening area of annular opening 34 in FIG. 5, in contrast with its large size area in FIG. 6, is believed to create, by the annular knife edge 20a, a venturi effect to increase the turbulence of the air striking the paint stream emerging from nozzle 13 so as to enhance dispersion of the paint.

Second, axial movement of member 20 relative to body portion 16 between the positions shown in FIGS. 5 and 6 controls the volume of paint sprayed through nozzle 13. It has been found that a larger volume of paint is sprayed with the parts in the FIG. 5 position than when they are in the FIG. 6 position. Hence, if reduction in spray volume is desired, member 20 is moved axially away from nozzle 13.

Third, it has been found that when the spray gun parts are in the FIG. 6 position and the operator releases his finger to uncover opening 16j to cut off the spraying action through nozzle 13, the paint in container 12 is agitated by the air under pressure entering by hose 14. It is believed that the air emerging from annular recess 16g in FIG. 6 strikes annular face 20 of member 20 so that some of this air travels in the direction of the arrows through annular opening 34, nozzle 13, bores 16c and 16b, bore 28a, the paint in container 12, opening 16h, bore 16g, conduit portion 16], and opening 16 to exhaust to the atmosphere. Also, at the moment of uncovering tie opening 161' by the operator, the pressure at nozzle 13: is greater than the pressure on top of the paint in container 12. Hence, release of the finger covering opening 16 not only cuts off the spraying action through nozzle 13 butalso causes an agitation of the paint in container 12 by the air under pressure in hose 14. Although the position in FIG. 6 gives the best agitation to the paint in container 12, movement of member 20 axially toward the FIG. 5 position in any of several different axial positions may still give some of this agitation.

The second and third features described in the last two paragraphs are believed to be caused by the control of the application of back air pressure onto the zone of nozzle opening 13 'by controlling the air flow from an nular opening 34 relative to spray nozzle 13. During spraying, the greatest diflerential pressure exists at spray nozzle 13 when the parts are in the FIG. 5 position, or the least differential pressure exists while the parts are in the PEG. 6 position since the air traveling in the direction of the arrows in FIG. 6 creates a back pressure on nozzle 13 to reduce the paint flow. Hence, the axial location of member 20, as shown by the positions in FIGS. 5 and 6, controls the application of the back air pressure to nozzle 13 so that: (1) the volume of paint sprayed through nozzle 13 is controlled while the perators finger covers hole 16j during application of the spraying air pressure, and (2) when spraying is not occurring and paint agitation is needed, the paint in container 12 is agitated by the air entering by hose 14 when the spraying pressure is cut off by uncovering hole 16 Hence, these two operations are selectively controlled by and automatically responsive to the air pressure control effected by the operators finger on hole 161' so that the spray gun has unique and simple operation and these operations each occur at the preferred time.

Various changes in details and arrangement of parts can be made by one skilled in the art without departing from either the spirit of this invention or the scope of the appended claims.

What is claimed is:

1. A spray gun for spraying liquid through a spray nozzle by fluid pressure, comprising means for cutting off or applying fluid pressure respectively to said liquid for causing or stopping liquid spraying, and control means for controlling the application of back fluid pressure to said nozzle for controlling the volume of liquid sprayed, said control means including a controller member having a bore surface surrounding said nozzle and movable axially relative to said nozzle, said controller member and nozzle having means responsive to movement of said bore surface in the downstream direction away from and relative to said nozzle for decreasing the volume of liquid sprayed by increasing said back pressure.

2. A spray gun for spraying liquid through a spray nozzle, comprising a spray head having said spray nozzle, a body portion, an adapter secured to said body portion and adapted to be secured to a container of said liquid to be sprayed, a liquid conduit for conveying said liquid from said container to said spray nozzle, and a fluid conduit; said fluid conduit having a first opening adapt-ed to be connected to a source of fluid pressure for spraying said liquid, having a second opening for conveying said fluid against said liquid for forcing said liquid through said spray nozzle, and having a third opening in said body portion adapted to be covered to cause liquid spraying by causing the fluid to travel from said first opening through said second opening in one direction or to be uncovered to stop spraying by causing the fluid from said first opening to exhaust to atmosphere through said third opening after by-passing said second opening, said second and third openings being located in two parallel flow circuits from said first opening, the pressure drop from fluid flow through said conduit being greater from said firstto second opening than from'said first to third opening so that fluid pressure on said liquid is quickly changed by controlling said third opening, said first opening being closer to said third opening than to said second opening and said second opening being substantially smaller in cross sectional area than said third opening so the fluid can readily escape through said un' covered third opening and spraying dribble will not occur by fluid pressure through said second opening, and means responsive to said spray cut oif condition and t0 the shape of said gun and to the fluid condition at said nozzle for agitating the liquid by causing said fluid to flow automatically in the reverse of said one direction through said nozzle, liquid and second opening to exhaust to the atmosphere through said third opening.

3. A spray gun for spraying liquid through a spray nozzle, comprising a spray head having said spray nozzle, a body portion, an adapter secured to said body portion and adapted to be secured to a container of said liquid to be sprayed, a liquid conduit for conveying said liquid from said container to said spray nozzle, and a fluid conduit; said fluid conduit having a first opening adapted to be connected to a source of fluid pressure f r spraying said liquid, having a second opening for conveying said fluid against said liquid for forcing said liquid through said spray nozzle, and having a third opening in said body portion adapted to be covered to cause liquid spraying by causing the fluid to travel from said first opening through said second opening in one direction or to be uncovered to stop spraying by causing the fluid from said first opening to exhaust to atmosphere through said third opening after by-passing said second opening, said second and third openings being located in two parallel flow circuits from said first opening, the pressure drop from fluid flow through said conduit being greater from said first to second opening than from said first to third opening so that fluid pressure on said liquid is quickly changed by controlling said third opening, said first opening being closer to said third opening than to said second opening and said second opening being substantially smaller in cross sectional area than said third opening so the fluid can readily escape through said uncovered third opening and spraying dribble will not occur by fluid pressure through said second opening, said fluid conduit being wholly in said body portion, said fluid conduit having a conduit portion connected to said third opening with a cross sectional area larger than said first and second opening and located in the fluid path between these last two mentioned openings, said body portion having a second fluid conduit from said first opening to a fourth opening in the zone of said spray nozzle and surrounding said spray nozzle, said spray head having a plug with a fluid controlling opening concentric with said spray nozzle to form with said body portion said fourth opening, and means mounting said plug and its fluid controlling opening for axial movement on said body portion relative to said spray nozzle for controlling the fluid flow from said fourth opening relative to said spray nozzle; said plug having an annular knife edge at said fourth opening providing a uniform outside diameter flow path at said nozzle in all axial positions, including means for decreasing the volume of liquid sprayed by increasing back fluid pressure on said nozzle during movement axially in the downstream direction away from said nozzle, and including means for agitating the liquid in one axial position by causing said fluid to flow along a single fluid flow path through said container and in thereverse of said one direction through said second opening to exhaust to atmosphere through said third opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,349,154 Holton Aug. 10, 1920 1,597,033 Gibbons Aug. 24, 1926 1,792,802 Brandt Feb. 17, 1931 1,899,749 Deutsch Feb. 28, 1933 2,014,942 Lemoine Sept. 17, 1935 2,071,218 Reid Feb. 16, 1937 FOREIGN PATENTS 1,135,173 France Sept. 17, 1956 

